To Stretch or Not to Stretch The Psoas

The backbone’s connected to the leg bone—this sounds simple, but it’s actually quite complicated. The first complication is, what is the fiber direction of the psoas? Well, that depends on whether you’re looking at the fibers above the pubic bone or below—because this muscle bends around a corner.

This article won’t tell you whether to stretch the psoas or not, but I will discuss a few different perspectives:

Stretching a muscle makes sense when you think that muscle has shrunk.

Stretching the psoas is complicated, because it crosses seven joints.

Creating a safe relationship can help the brain choose to reduce the muscle guarding.

Stretching The Psoas: It’s Complicated

One complication related to stretching the psoas is the joints it crosses. From the femur, the psoas crosses the hip ball and-socket joint; the strangely shaped sacroiliac joint; the lumbo-sacral joint, which has a disk in the middle and facets at the two sides; and four more lumbar joints, which all have disks and facets. That’s a lot of joints for one muscle to cross.

Which of these joints will feel the strain when the psoas is tight? The answer is different with each person—but a tight psoas on one side can lead to joint pain on the other side. That’s 14 possible locations for joint pain.

Here is another complication: When the psoas contracts, it not only flexes the hip, it also pulls the lumbars forward. The left psoas pulls only the left sides of the lumbars forward, which rotates the trunk to the right.

So, the psoas is not only a hip flexor, it is a trunk rotator. What’s complicated about that? Well, a tight left psoas may rotate the lumbars to the right, like a temporary rotoscoliosis.

Are you ready for the next complication? Since the psoas bends around the pubic bone, when the psoas is tight this pulls the pubic bone downward. This causes a shearing force at the sacroiliac joint, misalignment of the pubic symphysis or a pulling sensation in the groin.

There are more complications, but I would now like to return to a simpler idea: tight muscles.

In this photo, you can see that the psoas bends as it crosses the pubic bone. This femur is flexed. If the femur were in neutral or extended position, the bend in the psoas would be nearly 90 degrees.

What Is a Tight Muscle?

Massage school never taught me what makes a tight muscle tight. Over the years I have heard a number of models. Here are three.

1. A muscle may have shrunk, like a T-shirt shrinks in the dryer. Some say it’s the connective tissue that has shrunk rather than the muscle. Either way, the shrunken material model says some material has shrunk. When you subscribe to this model, naturally you want to stretch the muscle.

2. The voltage model says muscles shorten only when voltage arrives. The voltage originates in the brain and travels down the motor nerves to activate the muscles. In this model, muscles are like little machines called solenoids. In this model, a muscle is tight because it’s getting too much voltage. Will stretching help the brain reduce the voltage?

3. The defensive mind model says muscle tightness is a mental reaction to fear or danger. Will stretching help when the mind is feeling defensive?
Before we describe what happens during a psoas stretch, I would like to explain the physics of leverage on a simpler joint. If your tire is flat and you don’t have a jack, how are you going to lift a corner of a car?

No problem, if you happen to have a 110-inch beam and a dense block. Move the block so it is 10 inches from the bumper. Set the beam on the block. Put the short end of the beam under the car bumper. Now sit on the long end. If you weigh 150 pounds this will lift 1,500 pounds.

The thing most people do not consider in this scene is that your block must be strong enough to withstand a large compressive force. Whenever you use leverage, there is a fulcrum that receives compression. In our example, the block is the fulcrum. If it is not strong enough, it will be crushed to dust under 1,500 pounds of compression.

In massage school, I learned lots of muscle stretches. Each named which limb was the lever, but never named which joint is the fulcrum. So let’s look at a simple stretch and name the fulcrum.

When you stretch the quadriceps, the lever is the tibia. You hold the foot-end of the tibia and pull it to bend the knee. When your hand pulls the tibia, leverage pulls the quads longer. It’s about a 10-to-1 leverage.

So, nine pounds of pulling at the foot turns into 90 pounds of stretch. What joint is absorbing that 90 pounds of compressive force? The knee joint, where the femur meets the tibia. This is a nice, flat joint. The force is spread evenly across this wide surface.

While I don’t do any stretching at all, if I believed muscle tightness was a shrunken material, I would feel confident stretching the quads. I understand the fulcrum. I feel confident the two surfaces can take this compression.

To stretch the psoas, you pull the femur posteriorly, extending the hip. Eleven pounds of pull on the femur turns into 110 pounds of stretch. And where is the 110 pounds of compression going? I don’t know, because the psoas crosses seven joints.

Which of these joints takes the compressive force? The ball-socket joint? The sacroiliac joint? The lumbo-sacral joint? One of the facets? One of the disks? Where’s the fulcrum?

Will this compression be a wide, flat surface pressing into a wide, flat surface? Or will a small edge of bone take the whole concentrated force? Will the compression be straight in? Or will it be a twist, or a shear?

Stretching the psoas is complicated.

If Tightness is Voltage

To me, the word neuromuscular just means getting the brain (neuro) to reduce the voltage to the muscle (muscular). No technique makes the brain reduce the voltage, but you can influence the brain. Technique triggers the brain to reduce voltage, and results last when the client resolves or embraces her own tension. Relationship supports the brain to choose to reduce voltage.

The simplest neuromuscular technique is to hold pressure on a muscle. The pressure is not enough to stretch the fibers, but enough to send a signal up the muscle-sensory nerve to the brain. The brain responds by turning down the voltage. Then you feel the muscle soften or sink.

Applying a neuromuscular technique to the psoas can be challenging, because you have to press into the abdomen to access it. If you don’t have the knowledge, experience, skill and confidence to press into the abdomen and touch the psoas in a way the brain will perceive as safe, therapeutic and relaxing, then poking around in there might actually trigger the brain to increase voltage.

Neuromuscular techniques won’t succeed in inspiring the brain to turn down the voltage, unless you create a safe partnership with the client’s brain. You want the brain to see you as an ally or a partner.

How will the brain see you if it enacted muscle tension from fears and defenses, and you use leverage to force those muscles to stretch?

Swedish massage strokes the skin to send voltage up the skin-sensory nerves to the brain, and the brain interprets soothing skin strokes as nurturing. Human mothers and other animal mothers stroke their young, and the child’s brain then interprets that there is nothing in the world to worry about. Swedish massage creates a nurturing relationship that temporarily reduces voltage down to the muscles. When the brain trusts the therapist, motor nerve enervation is reduced, according to Arlene Montgomery in her book Neurobiology Essentials for Clinicians: What Every Therapist Needs to Know (Norton Series on Interpersonal Neurobiology, 2013).

During craniosacral and reiki, your hands rest softly on the body. The brain feels the light sensation and then, when trust builds, the brain sort of turns up the volume to hear more. Explained more fully, Lawrence H. Jones, D.O., calls this up-volume “signal gain,” in his book, Jones Strain-CounterStrain, written with Randall Kusunose, P.T., and Ed Goering, D.O. (Jones Strain-CounterStrain Inc., 1995). The brain increases the salience, or importance of, the motor signals, in Jones’ opinion. This leads to the brain making therapeutic changes.

So, it matters how the brain perceives you when it is time to decide whether to reduce the voltage or not. Does it perceive you as an ally? As safe, compassionate, present or accepting?

Relationship matters—especially when you are faced with a technically complex situation like the psoas.

Here, the yellow arrow represents a force applied downward on the femur, into extension. The yellow triangles represent the fulcrum—but where is the fulcrum in this stretch?

It’s Still Complicated

A few questions remain unanswered: I can’t answer whether stretching is helpful or not. I can’t answer whether muscles are tight because they have shrunk, because of voltage or defensiveness. I don’t know whether stretching the psoas is safe. I don’t know how the brain views those who attempt to stretch muscles with leverage. But you don’t need my answers.

You are more prepared now to answer for yourself.

In my experience, having had many therapists in my workshops, I have come to believe people get less from having experts answer questions for them, and more from having experts say they don’t have all the answers and to instead encourage students to think for themselves, to work it out from first principles.

This method is called the Socratic Method because it is how Socrates taught people in Athens, Greece. Now that you have examined the first principles of therapy, of stretching, for yourself, you are better prepared to draw your own conclusions.

A few questions can be answered: Things that are fine to do with other muscles may not be fine to do with the psoas. What you want to do to un-tighten muscles depends on your model of muscle tightness. You already know a few techniques that help the brain reduce voltage. More importantly, you already know how to create a relaxing partnership, which may resolve muscle tension beautifully.

About the Author

For 15 years before graduating from the Brian Utting School of Massage in 1994, Patrick Moore, L.M.T., intermittently taught algebra while working construction in Seattle, Washington. He has now taught his Melting Muscles continuing education workshops in 13 states, and practices massage in Tucson and Phoenix, Arizona. He also volunteers as a docent at the Arizona-Sonora Desert Museum.

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